Pop-up knob



FIG. 1 is a front perspective view of a pop up knob showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a left side view thereof; and,

FIG. 6 is a top view thereof.

The bottom view of the pop-up knob shown in the drawing figures does not form part of the claimed design. Drawing features shown in dashed lines do not form any part of the design claimed herein. 

The ornamental design for a pop-up knob, as shown and described. 